Objetive. This study analyses the impact that lexical representations of Spanish-speaking children in contexts of poverty have on the reading comprehension skills. Method. To this end, an assessment was made of the reading comprehension of 61 children. The results helped identify two groups within the sample: one with a high level of comprehension, and a second with a low level of comprehension. Each group’s vocabulary (semantic representations of the mental lexicon) and reading level (orthographic representations of the mental lexicon) was then assessed. Other important skills related to comprehension were likewise explored, such as working memory, inference-making ability, and morphosyntactic processing of spoken language. Results. The results provide evidence regarding the substantial impact of mental lexicon representations on reading comprehension.Objetivo. Analizar el impacto que las representaciones léxicas de niños hispanohablantes, que crecen en contextos de pobreza, tiene sobre la comprensión lectora. Método. Se evaluó a 61 niños en una prueba de comprensión lectora y, a partir de los resultados, se dividió la muestra total en dos grupos: un grupo de alto nivel de comprensión y otro grupo de bajo nivel. Luego, se evaluaron ambos grupos en pruebas de vocabulario (representaciones semánticas del léxico mental) y el nivel lector (representaciones ortográficas del léxico mental). Asimismo, se exploró el nivel de memoria operativa de los niños, la realización de inferencias y el procesamiento morfosintáctico de lenguaje oral. Resultados. Se obtienen resultados que otorgan evidencia sobre la incidencia del léxico mental en la comprensión de textos escritos.This study analyses the impact that lexical representations of Spanish-speaking children in contexts of poverty have on the reading comprehension skills. To this end, an assessment was made of the reading comprehension of 61 children. The results helped identify two groups within the sample: one with a high level of comprehension, and a second with a low level of comprehension. Each group’s vocabulary (semantic representations of the mental lexicon) and reading level (orthographic representations of the mental lexicon) was then assessed. Other important skills related to comprehension were likewise explored, such as working memory, inference-making ability, and morphosyntactic processing of spoken language. The results provide evidence regarding the substantial impact of mental lexicon representations on reading comprehension.This study analyses the impact that lexical representations of Spanish-speaking children in contexts of poverty have on the reading comprehension skills. To this end, an assessment was made of the reading comprehension of 61 children. The results helped identify two groups within the sample: one with a high level of comprehension, and a second with a low level of comprehension. Each group’s vocabulary (semantic representations of the mental lexicon) and reading level (orthographic representations of the mental lexicon) was then assessed. Other important skills related to comprehension were likewise explored, such as working memory, inference-making ability, and morphosyntactic processing of spoken language. The results provide evidence regarding the substantial impact of mental lexicon representations on reading comprehension.